Jordan and Evermann. Fishes of North America. 19 



10. HEXAXCIUS GllISEUS, (Gmeliii). 

 (Cow SHARK; CA|?A-BOTA.) 



Head large, depressed, blunt, the nostrils near tip of snout; no median 

 upper tooth; 2 011 each side entire, hooked outward; the next teeth 

 with or 7 cusps, the others similar; lower median tooth small, without 

 cusp ; lateral teeth each with 7 to 9 cusps, the number of denticles on 

 most of the teeth being thus greater than in H. corinus. Tail not twice 

 head, 3 in length, its upper scales enlarged; pectoral shorter than 

 lower jaw from gill opening. Color dark gray. (Day). L. 8 to 26 feet. A 

 very large shark inhabiting deep water, in the Mediterranean, thence 

 north to the west coasts of Scotland; also frequently taken in Cuba. 

 (Poey). (yriscua, gray.) (Eu.) 



Sqwilua grlseus, CMEI.IX, Syst. Nat., 1495, 1788, Mediterranean, after Broussonet. 



tijimlus grisew, BoNNATEBRE, Tabl. Encycl. Ichth., 9, 1788, Mediterranean, after Griset of 



Broussonet. 



XotHltintis griseus, GVNTHEB, Cat., vm, 397, 1870. 

 Notidanus griseus, DAY, British Fishes, 308, 1870. 

 Hexanchus griseus, POEY, Synopsis, 454, 1875. 



Order E. ASTEROSPONDYLI. 

 (THE TYPICAL SHARKS.) 



The essential character of this order is in the structure of the vertebrae. 

 The calcareous lamellae within each vertebra radiate from the central 

 ring. The group contains the great body of living sharks, including all 

 of those with 5 gill openings, 2 dorsals, and an anal fin. (acm/p, star; 

 an6v6vhos, vertebra.) 



SUBORDERS OP ASTEROSPONDYLI. 



a. Palatoquadrate apparatus articulated to preorbital part of skull; dorsal fins with spines. 



PROABTHBI. 

 rt. Palatoquadrate apparatus not articulated with the skull; no dorsal spines. ' AI.LI. 



Suborder PROARTHRI. 

 (THE CESTRACIONT SHARKS.) 



This group is characterized by the articulation of the palatoquadrate 

 apparatus by an extensive surface with the preorbital region of the skull. 

 Vertebras asterospoudylous. It consists of a single family, the HETERO- 

 DONTIIXK, which, like the preceding families, possesses much interest to 

 palaeontologists from its supposed relation to extinct forms, (npo, before ; 

 upBpav, joint; Cestracion,is an old name, from /carpa, a pickax ; the name 

 probably originally applied to Sphyrna.) 



Family VII. HETERODONTID^E. 



(THE BULLHEAD SHARKS.) 



Sharks with 2 dorsal fins, each provided with a strong spine; the 

 first dorsal opposite the space between pectorals and ventrals ; the 

 second in advance of the anal. Body elongate, obtusely trihedral, 



